ice: `expected type .. but found Lifetime..`

[matthiaskrgr]

auto-reduced (treereduce-rust):

type WithLifetime<T> = impl Equals<>;
fn _defining_use<T>() -> WithLifetime<T> {}

trait Convert<'a> {
    
    fn convert<'b, T: ?Sized>(, x: &'a T) -> &'b T;
}



fn extend_lifetime<'a, 'b, T: ?Sized>(x: &'a T) -> &'b T {
    WithLifetime::<&'a ()>::convert_helper::<(), T>(&(), x)
}

trait Equals {
    
    fn convert_helper<'a, 'b, W: , T: ?Sized>(
        ,
        ,
    ) -> &'b T;
}

impl<S> Equals for S {
    
    fn convert_helper<'foo, 'b, W: Convert<'a, >, T: ?Sized>(
        proof: &'b Self,
        x: &'a T,
    ) -> &'b T {
        W::convert(proof, x)
    }
}

original code

original:

#![feature(type_alias_impl_trait)]

type WithLifetime<T> = impl Equals<SelfType = ()>;
fn _defining_use<T>() -> WithLifetime<T> {}

trait Convert<'a> {
    type Witness;
    fn convert<'b, T: ?Sized>(_proof: &'b Self::Witness, x: &'a T) -> &'b T;
}

impl<'a> Convert<'a> for () {
    type Witness = WithLifetime<&'a ()>;

    fn convert<'b, T: ?Sized>(_proof: &'b WithLifetime<&'a ()>, x: &'a T) -> &'b T {
        // compiler used to think it gets to assume 'a: 'b here because
        // of the `&'b WithLifetime<&'a ()>` argument
        x
        //~^ ERROR lifetime may not live long enough
    }
}

fn extend_lifetime<'a, 'b, T: ?Sized>(x: &'a T) -> &'b T {
    WithLifetime::<&'a ()>::convert_helper::<(), T>(&(), x)
}

trait Equals {
    type SelfType;
    fn convert_helper<'a, 'b, W: Convert<'a, Witness = Self>, T: ?Sized>(
        proof: &'b Self::SelfType,
        x: &'a T,
    ) -> &'b T;
}

impl<S> Equals for S {
    type SelfType = Self;
    fn convert_helper<'foo, 'b, W: Convert<'a, Witness = Self>, T: ?Sized>(
        proof: &'b Self,
        x: &'a T,
    ) -> &'b T {
        W::convert(proof, x)
    }
}

fn main() {
    let r;
    {
        let x = String::from("Hello World?");
        r = extend_lifetime(&x);
    }
    println!("{}", r);
}

Version information

rustc 1.78.0-nightly (af88f7db5 2024-02-08)
binary: rustc
commit-hash: af88f7db51f6f2a1472f9279d7c7e7c822afff77
commit-date: 2024-02-08
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 17.0.6

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zpolymorphize=on -Zinline-mir=yes

Program output

error: expected argument name, found `,`
 --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:8:31
  |
8 |     fn convert<'b, T: ?Sized>(, x: &'a T) -> &'b T;
  |                               ^ expected argument name

error: expected argument name, found `,`
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:20:9
   |
20 |         ,
   |         ^ expected argument name

error: expected argument name, found `,`
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:21:9
   |
21 |         ,
   |         ^ expected argument name

error[E0261]: use of undeclared lifetime name `'a`
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:27:44
   |
27 |     fn convert_helper<'foo, 'b, W: Convert<'a, >, T: ?Sized>(
   |                                            ^^ undeclared lifetime
   |
   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the bound lifetime-generic with a new `'a` lifetime
   |
27 |     fn convert_helper<'foo, 'b, W: for<'a> Convert<'a, >, T: ?Sized>(
   |                                    +++++++
help: consider introducing lifetime `'a` here
   |
27 |     fn convert_helper<'a, 'foo, 'b, W: Convert<'a, >, T: ?Sized>(
   |                       +++
help: consider introducing lifetime `'a` here
   |
25 | impl<'a, S> Equals for S {
   |      +++

error[E0261]: use of undeclared lifetime name `'a`
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:29:13
   |
29 |         x: &'a T,
   |             ^^ undeclared lifetime
   |
help: consider introducing lifetime `'a` here
   |
27 |     fn convert_helper<'a, 'foo, 'b, W: Convert<'a, >, T: ?Sized>(
   |                       +++
help: consider introducing lifetime `'a` here
   |
25 | impl<'a, S> Equals for S {
   |      +++

error[E0658]: `impl Trait` in type aliases is unstable
 --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:3:24
  |
3 | type WithLifetime<T> = impl Equals<>;
  |                        ^^^^^^^^^^^^^
  |
  = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information
  = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable
  = note: this compiler was built on 2024-02-08; consider upgrading it if it is out of date

warning: anonymous parameters are deprecated and will be removed in the next edition
 --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:8:30
  |
8 |     fn convert<'b, T: ?Sized>(, x: &'a T) -> &'b T;
  |                              ^ help: try naming the parameter or explicitly ignoring it: `_: (`
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2018!
  = note: for more information, see issue #41686 <https://github.com/rust-lang/rust/issues/41686>
  = note: `#[warn(anonymous_parameters)]` on by default

warning: anonymous parameters are deprecated and will be removed in the next edition
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:19:46
   |
19 |     fn convert_helper<'a, 'b, W: , T: ?Sized>(
   |                                              ^ help: try naming the parameter or explicitly ignoring it: `_: (`
   |
   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2018!
   = note: for more information, see issue #41686 <https://github.com/rust-lang/rust/issues/41686>

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:33:2
   |
33 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs`

error[E0195]: lifetime parameters or bounds on method `convert_helper` do not match the trait declaration
  --> /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:27:22
   |
19 |     fn convert_helper<'a, 'b, W: , T: ?Sized>(
   |                      ------------------------ lifetimes in impl do not match this method in trait
...
27 |     fn convert_helper<'foo, 'b, W: Convert<'a, >, T: ?Sized>(
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetimes do not match method in trait

error: internal compiler error: compiler/rustc_middle/src/ty/generic_args.rs:915:9: expected type for `W/#1` (W/#1/1) but found Lifetime(ReErased) when substituting, args=[(), ReErased, (), T/#1]

thread 'rustc' panicked at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/compiler/rustc_errors/src/lib.rs:922:30:
Box<dyn Any>
stack backtrace:
   0:     0x7faf1c58bdd6 - std::backtrace_rs::backtrace::libunwind::trace::hf92ca961e56825b0
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7faf1c58bdd6 - std::backtrace_rs::backtrace::trace_unsynchronized::h23f341cc1a6c507f
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7faf1c58bdd6 - std::sys_common::backtrace::_print_fmt::ha5a5ba44893edc7f
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7faf1c58bdd6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h667e6ba5a1d3724e
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7faf1c5de830 - core::fmt::rt::Argument::fmt::h06c91f49bef095fb
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/core/src/fmt/rt.rs:142:9
   5:     0x7faf1c5de830 - core::fmt::write::h8e4b31b0aa81d13f
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/core/src/fmt/mod.rs:1120:17
   6:     0x7faf1c57f64f - std::io::Write::write_fmt::h4c479f5c53dfe78c
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/io/mod.rs:1854:15
   7:     0x7faf1c58bbb4 - std::sys_common::backtrace::_print::he414f5864df55ed1
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7faf1c58bbb4 - std::sys_common::backtrace::print::h939e58bdcc61d57d
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7faf1c58e947 - std::panicking::default_hook::{{closure}}::h244e48e05cd664b2
  10:     0x7faf1c58e6a9 - std::panicking::default_hook::hf842080c39497dac
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/panicking.rs:292:9
  11:     0x7faf1f3454ac - std[f801e042bca9681]::panicking::update_hook::<alloc[1377227f5558ef79]::boxed::Box<rustc_driver_impl[65af58b05c4f91ef]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7faf1c58f096 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hee9c09a26ce84f59
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/alloc/src/boxed.rs:2029:9
  13:     0x7faf1c58f096 - std::panicking::rust_panic_with_hook::h83c20f9191a2a712
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/panicking.rs:785:13
  14:     0x7faf1f376f04 - std[f801e042bca9681]::panicking::begin_panic::<rustc_errors[89ec94d63507ad05]::ExplicitBug>::{closure#0}
  15:     0x7faf1f3735f6 - std[f801e042bca9681]::sys_common::backtrace::__rust_end_short_backtrace::<std[f801e042bca9681]::panicking::begin_panic<rustc_errors[89ec94d63507ad05]::ExplicitBug>::{closure#0}, !>
  16:     0x7faf1f36ea66 - std[f801e042bca9681]::panicking::begin_panic::<rustc_errors[89ec94d63507ad05]::ExplicitBug>
  17:     0x7faf1f382b61 - <rustc_errors[89ec94d63507ad05]::diagnostic_builder::BugAbort as rustc_errors[89ec94d63507ad05]::diagnostic_builder::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7faf1f7369be - <rustc_errors[89ec94d63507ad05]::DiagCtxt>::bug::<alloc[1377227f5558ef79]::string::String>
  19:     0x7faf1f7d23db - rustc_middle[2cc1c6e52ad3d43f]::util::bug::opt_span_bug_fmt::<rustc_span[467c297c964200f6]::span_encoding::Span>::{closure#0}
  20:     0x7faf1f7b990a - rustc_middle[2cc1c6e52ad3d43f]::ty::context::tls::with_opt::<rustc_middle[2cc1c6e52ad3d43f]::util::bug::opt_span_bug_fmt<rustc_span[467c297c964200f6]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7faf1f7b9788 - rustc_middle[2cc1c6e52ad3d43f]::ty::context::tls::with_context_opt::<rustc_middle[2cc1c6e52ad3d43f]::ty::context::tls::with_opt<rustc_middle[2cc1c6e52ad3d43f]::util::bug::opt_span_bug_fmt<rustc_span[467c297c964200f6]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7faf1d767db0 - rustc_middle[2cc1c6e52ad3d43f]::util::bug::bug_fmt
  23:     0x7faf1f7c7712 - <rustc_middle[2cc1c6e52ad3d43f]::ty::generic_args::ArgFolder>::type_param_expected
  24:     0x7faf20607464 - <rustc_middle[2cc1c6e52ad3d43f]::ty::generic_args::ArgFolder as rustc_type_ir[7a3f94f8b621150f]::fold::TypeFolder<rustc_middle[2cc1c6e52ad3d43f]::ty::context::TyCtxt>>::fold_ty
  25:     0x7faf2131ef4c - rustc_mir_transform[f04df7d082cb6ded]::inline::cycle::mir_callgraph_reachable::process
  26:     0x7faf2131e2ee - rustc_mir_transform[f04df7d082cb6ded]::inline::cycle::mir_callgraph_reachable
  27:     0x7faf2131e1e9 - rustc_query_impl[5ca841c3c79670ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5ca841c3c79670ea]::query_impl::mir_callgraph_reachable::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 1usize]>>
  28:     0x7faf2131e1ab - <rustc_query_impl[5ca841c3c79670ea]::query_impl::mir_callgraph_reachable::dynamic_query::{closure#2} as core[30be359c16b30868]::ops::function::FnOnce<(rustc_middle[2cc1c6e52ad3d43f]::ty::context::TyCtxt, (rustc_middle[2cc1c6e52ad3d43f]::ty::instance::Instance, rustc_span[467c297c964200f6]::def_id::LocalDefId))>>::call_once
  29:     0x7faf2131db1d - rustc_query_system[125a8aa150dcabe3]::query::plumbing::try_execute_query::<rustc_query_impl[5ca841c3c79670ea]::DynamicConfig<rustc_query_system[125a8aa150dcabe3]::query::caches::DefaultCache<(rustc_middle[2cc1c6e52ad3d43f]::ty::instance::Instance, rustc_span[467c297c964200f6]::def_id::LocalDefId), rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[5ca841c3c79670ea]::plumbing::QueryCtxt, false>
  30:     0x7faf2131d85e - rustc_query_impl[5ca841c3c79670ea]::query_impl::mir_callgraph_reachable::get_query_non_incr::__rust_end_short_backtrace
  31:     0x7faf210b57fb - <rustc_mir_transform[f04df7d082cb6ded]::inline::Inliner>::try_inlining
  32:     0x7faf210b1b86 - <rustc_mir_transform[f04df7d082cb6ded]::inline::Inliner>::process_blocks
  33:     0x7faf20806363 - <rustc_mir_transform[f04df7d082cb6ded]::inline::Inline as rustc_middle[2cc1c6e52ad3d43f]::mir::MirPass>::run_pass
  34:     0x7faf206123e6 - rustc_mir_transform[f04df7d082cb6ded]::pass_manager::run_passes_inner
  35:     0x7faf209afecd - rustc_mir_transform[f04df7d082cb6ded]::optimized_mir
  36:     0x7faf20674735 - rustc_query_impl[5ca841c3c79670ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5ca841c3c79670ea]::query_impl::optimized_mir::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 8usize]>>
  37:     0x7faf20674d21 - rustc_query_system[125a8aa150dcabe3]::query::plumbing::try_execute_query::<rustc_query_impl[5ca841c3c79670ea]::DynamicConfig<rustc_query_system[125a8aa150dcabe3]::query::caches::DefIdCache<rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[5ca841c3c79670ea]::plumbing::QueryCtxt, false>
  38:     0x7faf2067455e - rustc_query_impl[5ca841c3c79670ea]::query_impl::optimized_mir::get_query_non_incr::__rust_end_short_backtrace
  39:     0x7faf2084199b - rustc_middle[2cc1c6e52ad3d43f]::query::plumbing::query_get_at::<rustc_query_system[125a8aa150dcabe3]::query::caches::DefIdCache<rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 8usize]>>>
  40:     0x7faf20fd91af - rustc_query_impl[5ca841c3c79670ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5ca841c3c79670ea]::query_impl::unused_generic_params::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 4usize]>>
  41:     0x7faf20fd8973 - rustc_query_system[125a8aa150dcabe3]::query::plumbing::try_execute_query::<rustc_query_impl[5ca841c3c79670ea]::DynamicConfig<rustc_query_system[125a8aa150dcabe3]::query::caches::DefaultCache<rustc_middle[2cc1c6e52ad3d43f]::ty::instance::InstanceDef, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 4usize]>>, false, false, false>, rustc_query_impl[5ca841c3c79670ea]::plumbing::QueryCtxt, false>
  42:     0x7faf20fd865c - rustc_query_impl[5ca841c3c79670ea]::query_impl::unused_generic_params::get_query_non_incr::__rust_end_short_backtrace
  43:     0x7faf20fd45da - rustc_interface[c2746bee48761670]::passes::analysis
  44:     0x7faf20fd3bdf - rustc_query_impl[5ca841c3c79670ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5ca841c3c79670ea]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 1usize]>>
  45:     0x7faf212a17b2 - rustc_query_system[125a8aa150dcabe3]::query::plumbing::try_execute_query::<rustc_query_impl[5ca841c3c79670ea]::DynamicConfig<rustc_query_system[125a8aa150dcabe3]::query::caches::SingleCache<rustc_middle[2cc1c6e52ad3d43f]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[5ca841c3c79670ea]::plumbing::QueryCtxt, false>
  46:     0x7faf212a1515 - rustc_query_impl[5ca841c3c79670ea]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  47:     0x7faf212e2436 - rustc_interface[c2746bee48761670]::interface::run_compiler::<core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>, rustc_driver_impl[65af58b05c4f91ef]::run_compiler::{closure#0}>::{closure#0}
  48:     0x7faf20f60248 - std[f801e042bca9681]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[c2746bee48761670]::util::run_in_thread_with_globals<rustc_interface[c2746bee48761670]::util::run_in_thread_pool_with_globals<rustc_interface[c2746bee48761670]::interface::run_compiler<core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>, rustc_driver_impl[65af58b05c4f91ef]::run_compiler::{closure#0}>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>
  49:     0x7faf20f60077 - <<std[f801e042bca9681]::thread::Builder>::spawn_unchecked_<rustc_interface[c2746bee48761670]::util::run_in_thread_with_globals<rustc_interface[c2746bee48761670]::util::run_in_thread_pool_with_globals<rustc_interface[c2746bee48761670]::interface::run_compiler<core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>, rustc_driver_impl[65af58b05c4f91ef]::run_compiler::{closure#0}>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[30be359c16b30868]::result::Result<(), rustc_span[467c297c964200f6]::ErrorGuaranteed>>::{closure#1} as core[30be359c16b30868]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  50:     0x7faf1c598735 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h99757397e7c4fa77
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/alloc/src/boxed.rs:2015:9
  51:     0x7faf1c598735 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h7e0e3d311e6447da
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/alloc/src/boxed.rs:2015:9
  52:     0x7faf1c598735 - std::sys::pal::unix::thread::Thread::new::thread_start::h0eb0f22e3002fa19
                               at /rustc/af88f7db51f6f2a1472f9279d7c7e7c822afff77/library/std/src/sys/pal/unix/thread.rs:108:17
  53:     0x7faf1c3839eb - <unknown>
  54:     0x7faf1c4077cc - <unknown>
  55:                0x0 - <unknown>

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.78.0-nightly (af88f7db5 2024-02-08) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z polymorphize=on -Z inline-mir=yes -Z dump-mir-dir=dir

query stack during panic:
#0 [mir_callgraph_reachable] computing if `<impl at /tmp/icemaker_global_tempdir.smWWDFyFinWB/rustc_testrunner_tmpdir_reporting.PwzVr2WO2dCz/mvce.rs:25:1: 25:21>::convert_helper::<'_, ()>` (transitively) calls `extend_lifetime`
#1 [optimized_mir] optimizing MIR for `extend_lifetime`
#2 [unused_generic_params] determining which generic parameters are unused by `extend_lifetime`
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 9 previous errors; 2 warnings emitted

Some errors have detailed explanations: E0195, E0261, E0601, E0658.
For more information about an error, try `rustc --explain E0195`.

[matthiaskrgr]

auto-reduced (treereduce-rust):

impl Trait<()> for () {
    fn foo<'a, K>(self, _: (), _: K) {
        todo!();
    }
}

trait Foo<T> {}

impl<F, T> Foo<T> for F {
    fn main() {
        ().foo((), ());
    }
}

trait Trait<T> {
    fn foo<'a, K>(self, _: T, _: K)
    where
        T: 'a,
        K: 'a;
}

original:

trait Bar<T> {
    fn foo<'a, K>(self, _: T, _: K) where K: 'a, K: 'main;
}

impl Trait<()> for () {
    fn foo<'a, K>(self, _: (), _: K) where { //~ ERROR E0195
        todo!();
    }
}

struct State;

trait Foo<T> {
    fn foo<'a>(&self, state: &'a State) -> &'a T
    where
        T: 'a;
}

impl<F, T> Foo<T> for F
where
    F: Fn(&State) -> &T,
{
    fn main() {
    ().foo((), ());
}
}

trait Trait<T> {
    fn foo<'a, K>(self, _: T, _: K) where T: 'a, K: 'a;
}

impl Bar for () {
    fn foo<'a: 'a>(&'a self) {} //~ ERROR E0195
}

fn main() {
    self(state);
}

Version information

rustc 1.79.0-nightly (8b2459c1f 2024-04-09)
binary: rustc
commit-hash: 8b2459c1f21187f9792d99310171a15e64feb9cf
commit-date: 2024-04-09
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.3

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zpolymorphize=on -Zinline-mir=yes

Program output

error[E0407]: method `main` is not a member of trait `Foo`
  --> /tmp/icemaker_global_tempdir.3Q51z5KKvcCT/rustc_testrunner_tmpdir_reporting.fhYfT0a7niEy/mvce.rs:10:5
   |
10 | /     fn main() {
11 | |         ().foo((), ());
12 | |     }
   | |_____^ not a member of trait `Foo`

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.3Q51z5KKvcCT/rustc_testrunner_tmpdir_reporting.fhYfT0a7niEy/mvce.rs:20:2
   |
20 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.3Q51z5KKvcCT/rustc_testrunner_tmpdir_reporting.fhYfT0a7niEy/mvce.rs`

error[E0195]: lifetime parameters or bounds on method `foo` do not match the trait declaration
  --> /tmp/icemaker_global_tempdir.3Q51z5KKvcCT/rustc_testrunner_tmpdir_reporting.fhYfT0a7niEy/mvce.rs:2:11
   |
2  |     fn foo<'a, K>(self, _: (), _: K) {
   |           ^^^^^^^ lifetimes do not match method in trait
...
16 |     fn foo<'a, K>(self, _: T, _: K)
   |           ------- lifetimes in impl do not match this method in trait
17 |     where
18 |         T: 'a,
   |            -- this bound might be missing in the impl
19 |         K: 'a;
   |            -- this bound might be missing in the impl

error: internal compiler error: compiler/rustc_middle/src/ty/generic_args.rs:904:9: expected type for `K/#0` (K/#0/0) but found Lifetime('{erased}) when instantiating, args=['{erased}, ()]

thread 'rustc' panicked at compiler/rustc_middle/src/ty/generic_args.rs:904:9:
Box<dyn Any>
stack backtrace:
   0:     0x77b08cce7885 - std::backtrace_rs::backtrace::libunwind::trace::hdbe9796987ceb0c3
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x77b08cce7885 - std::backtrace_rs::backtrace::trace_unsynchronized::h2e6c5a328606b599
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x77b08cce7885 - std::sys_common::backtrace::_print_fmt::hcd61867f45f7a64e
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x77b08cce7885 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::he7a3bc3921692656
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x77b08cd36abb - core::fmt::rt::Argument::fmt::h95836dbf862f7d1b
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/core/src/fmt/rt.rs:142:9
   5:     0x77b08cd36abb - core::fmt::write::hffa81a05ea2c737d
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/core/src/fmt/mod.rs:1153:17
   6:     0x77b08ccdc3ff - std::io::Write::write_fmt::ha28139dc2458ce78
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/io/mod.rs:1843:15
   7:     0x77b08cce765e - std::sys_common::backtrace::_print::hadc6ec3a0cb53db2
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x77b08cce765e - std::sys_common::backtrace::print::h9cc206a8a46a519b
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x77b08ccea159 - std::panicking::default_hook::{{closure}}::h72365f66652b6097
  10:     0x77b08cce9e75 - std::panicking::default_hook::h296340dc5ed32378
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/panicking.rs:291:9
  11:     0x77b08966367e - std[2474eec217f17911]::panicking::update_hook::<alloc[f48ecbf8778ab0f6]::boxed::Box<rustc_driver_impl[1fb95cb326290392]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x77b08ccea85c - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h4df439e5fb4fe29f
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/alloc/src/boxed.rs:2032:9
  13:     0x77b08ccea85c - std::panicking::rust_panic_with_hook::hb888ecdc252dbf69
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/panicking.rs:792:13
  14:     0x77b089693544 - std[2474eec217f17911]::panicking::begin_panic::<rustc_errors[891d7395ead1ce18]::ExplicitBug>::{closure#0}
  15:     0x77b089690466 - std[2474eec217f17911]::sys_common::backtrace::__rust_end_short_backtrace::<std[2474eec217f17911]::panicking::begin_panic<rustc_errors[891d7395ead1ce18]::ExplicitBug>::{closure#0}, !>
  16:     0x77b089690146 - std[2474eec217f17911]::panicking::begin_panic::<rustc_errors[891d7395ead1ce18]::ExplicitBug>
  17:     0x77b08969d441 - <rustc_errors[891d7395ead1ce18]::diagnostic::BugAbort as rustc_errors[891d7395ead1ce18]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x77b089b3ff8c - rustc_middle[c40ba118dc41381f]::util::bug::opt_span_bug_fmt::<rustc_span[7fcb37ac6fbeabc]::span_encoding::Span>::{closure#0}
  19:     0x77b089b273ca - rustc_middle[c40ba118dc41381f]::ty::context::tls::with_opt::<rustc_middle[c40ba118dc41381f]::util::bug::opt_span_bug_fmt<rustc_span[7fcb37ac6fbeabc]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x77b089b2724b - rustc_middle[c40ba118dc41381f]::ty::context::tls::with_context_opt::<rustc_middle[c40ba118dc41381f]::ty::context::tls::with_opt<rustc_middle[c40ba118dc41381f]::util::bug::opt_span_bug_fmt<rustc_span[7fcb37ac6fbeabc]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x77b087753960 - rustc_middle[c40ba118dc41381f]::util::bug::bug_fmt
  22:     0x77b089b31b72 - <rustc_middle[c40ba118dc41381f]::ty::generic_args::ArgFolder>::type_param_expected
  23:     0x77b08aa0af59 - <rustc_middle[c40ba118dc41381f]::ty::generic_args::ArgFolder as rustc_type_ir[359712355f3f4dcc]::fold::TypeFolder<rustc_middle[c40ba118dc41381f]::ty::context::TyCtxt>>::fold_ty
  24:     0x77b08b029c51 - <rustc_mir_transform[86f15631b6fc49c9]::inline::Inliner>::try_inlining
  25:     0x77b08b0475d0 - <rustc_mir_transform[86f15631b6fc49c9]::inline::Inliner>::process_blocks
  26:     0x77b08b0214b9 - <rustc_mir_transform[86f15631b6fc49c9]::inline::Inline as rustc_middle[c40ba118dc41381f]::mir::MirPass>::run_pass
  27:     0x77b08aa0190d - rustc_mir_transform[86f15631b6fc49c9]::pass_manager::run_passes_inner
  28:     0x77b08b0316b1 - rustc_mir_transform[86f15631b6fc49c9]::optimized_mir
  29:     0x77b08b03089b - rustc_query_impl[441f0dd3998ce1f3]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[441f0dd3998ce1f3]::query_impl::optimized_mir::dynamic_query::{closure#2}::{closure#0}, rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 8usize]>>
  30:     0x77b08abb8021 - rustc_query_system[34c3e53911c1ab13]::query::plumbing::try_execute_query::<rustc_query_impl[441f0dd3998ce1f3]::DynamicConfig<rustc_query_system[34c3e53911c1ab13]::query::caches::DefIdCache<rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[441f0dd3998ce1f3]::plumbing::QueryCtxt, false>
  31:     0x77b08abb7762 - rustc_query_impl[441f0dd3998ce1f3]::query_impl::optimized_mir::get_query_non_incr::__rust_end_short_backtrace
  32:     0x77b08ad4bcb6 - rustc_middle[c40ba118dc41381f]::query::plumbing::query_get_at::<rustc_query_system[34c3e53911c1ab13]::query::caches::DefIdCache<rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 8usize]>>>
  33:     0x77b08b305887 - rustc_query_impl[441f0dd3998ce1f3]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[441f0dd3998ce1f3]::query_impl::unused_generic_params::dynamic_query::{closure#2}::{closure#0}, rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 4usize]>>
  34:     0x77b08b305059 - rustc_query_system[34c3e53911c1ab13]::query::plumbing::try_execute_query::<rustc_query_impl[441f0dd3998ce1f3]::DynamicConfig<rustc_query_system[34c3e53911c1ab13]::query::caches::DefaultCache<rustc_middle[c40ba118dc41381f]::ty::instance::InstanceDef, rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 4usize]>>, false, false, false>, rustc_query_impl[441f0dd3998ce1f3]::plumbing::QueryCtxt, false>
  35:     0x77b08b304d4e - rustc_query_impl[441f0dd3998ce1f3]::query_impl::unused_generic_params::get_query_non_incr::__rust_end_short_backtrace
  36:     0x77b08b300880 - rustc_interface[bf8f900257cf37fb]::passes::analysis
  37:     0x77b08b2ff595 - rustc_query_impl[441f0dd3998ce1f3]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[441f0dd3998ce1f3]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 1usize]>>
  38:     0x77b08b858e65 - rustc_query_system[34c3e53911c1ab13]::query::plumbing::try_execute_query::<rustc_query_impl[441f0dd3998ce1f3]::DynamicConfig<rustc_query_system[34c3e53911c1ab13]::query::caches::SingleCache<rustc_middle[c40ba118dc41381f]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[441f0dd3998ce1f3]::plumbing::QueryCtxt, false>
  39:     0x77b08b858bc9 - rustc_query_impl[441f0dd3998ce1f3]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  40:     0x77b08b6ee814 - rustc_interface[bf8f900257cf37fb]::interface::run_compiler::<core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>, rustc_driver_impl[1fb95cb326290392]::run_compiler::{closure#0}>::{closure#0}
  41:     0x77b08b7c0e1d - std[2474eec217f17911]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[bf8f900257cf37fb]::util::run_in_thread_with_globals<rustc_interface[bf8f900257cf37fb]::util::run_in_thread_pool_with_globals<rustc_interface[bf8f900257cf37fb]::interface::run_compiler<core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>, rustc_driver_impl[1fb95cb326290392]::run_compiler::{closure#0}>::{closure#0}, core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>>::{closure#0}, core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>>
  42:     0x77b08b7c0c2a - <<std[2474eec217f17911]::thread::Builder>::spawn_unchecked_<rustc_interface[bf8f900257cf37fb]::util::run_in_thread_with_globals<rustc_interface[bf8f900257cf37fb]::util::run_in_thread_pool_with_globals<rustc_interface[bf8f900257cf37fb]::interface::run_compiler<core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>, rustc_driver_impl[1fb95cb326290392]::run_compiler::{closure#0}>::{closure#0}, core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>>::{closure#0}, core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[21d3ad91760ee510]::result::Result<(), rustc_span[7fcb37ac6fbeabc]::ErrorGuaranteed>>::{closure#1} as core[21d3ad91760ee510]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  43:     0x77b08ccf428b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hd1b00ae2ddfcdaf0
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/alloc/src/boxed.rs:2018:9
  44:     0x77b08ccf428b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h9b7565e262650825
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/alloc/src/boxed.rs:2018:9
  45:     0x77b08ccf428b - std::sys::pal::unix::thread::Thread::new::thread_start::h7f0b25bf4ebb2e1b
                               at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library/std/src/sys/pal/unix/thread.rs:108:17
  46:     0x77b0864a955a - <unknown>
  47:     0x77b086526a3c - <unknown>
  48:                0x0 - <unknown>

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.79.0-nightly (8b2459c1f 2024-04-09) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z polymorphize=on -Z inline-mir=yes -Z dump-mir-dir=dir

query stack during panic:
#0 [optimized_mir] optimizing MIR for `<impl at /tmp/icemaker_global_tempdir.3Q51z5KKvcCT/rustc_testrunner_tmpdir_reporting.fhYfT0a7niEy/mvce.rs:9:1: 9:24>::main`
#1 [unused_generic_params] determining which generic parameters are unused by `<impl at /tmp/icemaker_global_tempdir.3Q51z5KKvcCT/rustc_testrunner_tmpdir_reporting.fhYfT0a7niEy/mvce.rs:9:1: 9:24>::main`
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors

Some errors have detailed explanations: E0195, E0407, E0601.
For more information about an error, try `rustc --explain E0195`.